This is Medano Creek, a shallow creek that runs in the spring due to the snow melt from the Sangre De Cristo mountains to the north. You have to wade through it to get to the dunes from the parking lot.
A shot of the night sky, next to the highway where we slept in our car. I was getting the camera set up to do a 2-hour continuous exposure for star trails. The sand dunes are just underneath the mountain silhouette but you can't really see them here. There were elk roaming the grass in the foreground and coyotes hauling off in the distance.